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AN ACCOUNT OF THE 
HABITS, CHANGES, AND DISEASES 



OF THE 



OMBYX MO 

OR 



Kl: 



Common Silkworm 






COMPILED BY THE 



;OYS' SILK CULTURE ASSOCIATION of the United 



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States, from Personal Experience and the Works 
of Various Standard Authorities. 



PRICE 25 CENTS 






Entered according to Act of Congress, in the year i88r, by the Hoys' Silk 

Culture Association of the United States, in the Office of ihe 

Librarian of Congress, at Washington, DC. 









SF5 



INTRODUCTION. 

The silkworm is a native of China. The silk 
industry was first introduced into Europe about the 
middle of the sixth century (552 A. D.), by two 
Persian monks, who brought a few silkworm's eggs 
from China in a hollow cane, in order to avoid 
detection. The worms proceeding from these eggs 
were carefully reared by the monks until they spun 
cocoons. They were the ancestors of those count- 
less numbers of silkworms now in existence in 
Europe and Western Asia. 

The silkworm is the caterpillar of the silkworm 
moth, which belongs to the family Bombycidce, 
genus Bombyx, of that branch of lepidopterous in- 
sects known as moths. Like all other insects, it un- 
dergoes two complete transformations during its 
lifetime. 

The full-grown worm is two and a half or three 
inches long. If now examined, it will be ascertained 
to have sixteen legs arranged in pairs : the first three 
pairs are attached to the first three rings of the body, 
and are called " true legs," being the only ones that 
are retained in the moth state ; the next three rings 
of the body are without legs; the other five pairs of 



legs are called " holders," and exist only in the cater- 
pillar, being used in climbing. 

On each side of every ring of the body may be 
observed a small hole, surrounded by a black ring : 
these are the spiracles or breathing holes, the or- 
gans of respiration in insects. 

The silk is produced from two reservoirs ex- 
tending the whole length of the body and uniting 
in the spinneret at the mouth. When about to spin* 
these reservoirs become very much enlarged, The 
silk exists in the body of the worm as a yellow gum. 
If it be taken from a cocoon and examined under a 
microscope, it will be found to be composed of two 
fibres, being derived alike from the two reservoirs. 
These fibres are made to cohere by a gummy sub- 
stance secreted by a number of glands situated on 
each side of the body near the mouth. 

The silkworm has fourteen eyes, seven on each 
side of the head, near the mouth,which has a vertical 
instead of a horizontal opening. The worm, after 
having wrapped itself up in the cocoon, is called 
a. pupa, or "chrysalis"; and on emerging from the 
cocoon, it is called an imago. 

The silk is wound from the cocoon by a pro- 
cess called reeling. It is then sent to the throwster, 
who unites several threads of reeled silk and twists 
them ; afterward to the dyer, when it is ready for 
weaving. 



SECTION I. 

THE CATERPILLAR PERIOD. 

As soon in the spring as the mulberry leaves 
have attained sufficient size to be given to the young 
silkworms, which in this climate is about the mid- 
dle of May, the eggs may be brought out from the 
place where they have been kept during the winter, 
and placed in the cocoonery. Keep them out of 
the sun ; the natural temperature will be sufficient 
to hatch them. The direct rays of the sun, or its 
reflection, are found to be injurious to the eggs, the 
worms, and the moths. 

About the ninth day after the eggs have been 
placed in the rearing apartment, or cocoonery, they 
will become lighter in color, and the worms may 
be seen curled up inside. When about to hatch — 
(they usually hatch on the tenth day after they are 
brought into the cocoonery) — they should have 
pieces of white mosquito netting placed over them, 
and on top of this a few white mulberry leaves, 
chopped into small pieces. The worms, as soon as 
hatched, will crawl up through the meshes of the 
mosquito netting on to the leaves, and at once 
begin to eat. They will hatch in the morning 
from daybreak until eight or nine o'clock. 

When first hatched, it is of a black color, 
which is due to a number of hairs with which the 



young worm is covered. This black color, however, 
gradually disappears, and is replaced by that of a 
dingy white. 

Young worms continue to increase in size 
.until they cast their skin, or " moult," a period 
varying, according to the temperature in which 
they are reared, from four to eight days. When 
moulting, they erect their heads and cease to eat. 
They moult either four or five times during their 
caterpillar life, which lasts, in this latitude, from 
four to five weeks. 

The period from hatching until the first moult- 
ing is called the first age) from the first until the 
second moulting, the second age, etc. 

In order to insure success in rearing silkworms, 
the following must- be particularly attended to, viz : 

I. Only worms that are hatched on the same 
day should be kept together. By keeping worms 
hatched on different days apart, you will save a 
great amount of labor, as the worms will, by this 
arrangement, all moult at the same time. 

II. No regular number of times for feeding the 
worms can be assigned ; they should be fed as often 
as the leaves become dry or are consumed. 

III. Feed the worms on the leaves of the 
Mortis alba, or w 7 hite mulberry, if procurable ; if 
not, those of the black or red mulberry, or of 
the Madura aitrantiaca, or osage orange, may be 

6 



substituted. Those of the white mulberry are 
preferable, for — - 

First — The tree bears leaves earlier in the 
spring; 

Second — A greater amount] of leaves are fur- 
nished in a shorter period of time ; 

Third — The silk produced from these leaves is 
of that sort most desired by the manufacturers. 

IV. Should any worms hatch before the above- 
named leaves are procurable, substitutes must be 
given, such as lettuce, or even tender cabbage leaves ; 
but they will not thrive on this kind of diet during 
their last ages. 

V. Young worms must have the leaves chopped 
up for them during the first three ages. This saves 
a great waste of leaves and is also a great advantage 
to the young worms ; because the smaller the 
leaves are cut the greater is the number of fresh- 
cut edges that exist, and the greater the number 
of worms that can be fed on this amount of leaves. 

VI. Do not allow the leaves on the trays to 
ferment, as the odor from fermented leaves will tend 
to generate diseases. 

VII. The litter must be allowed to remain on 
the trays while the worms on them are moulting; 
for the worm, during its sickness, does not like to 
be disturbed. 



VIII. Tobacco in every form should be kept 
away from the cocoonery, and much caution must 
be taken to keep it free from rats, mice, birds, and 
insects. 

IX. Most of the diseases to which silkworms are 
liable are caused by foul air, dampness, or defective 
management. Charcoal or chloride of lime should 
always be kept in the cocoonery, and must occa- 
sionally be renewed. 

X. The amount of leaves consumed by the 
produce of ^ oz. eggs (about 10,000) is as follows : 

During the first age 



second 


age 


third 


a 


fourth 


u 


fifth 


a 



iy 2 


fbs. 


AV2 


u 


is 


it 


45 


it 


274^ 


u 



XL The temperature during the caterpillar 
period must not be allowed to fall below 70 ° Fahr., 
but should be kept above that point by artificial 
means ; should the air become too hot, its temperature 
may be lowered somewhat by sprinkling the floor 
with w 7 ater,but the worms ought never to be deprived 
of the great benefits arising from keeping the air 
continually in circulation throughout the rearing 
apartment. The temperature should be maintained 
as even as possible, as any sudden change is disas- 
trous to the health of the worms. 



XII. One hundred worms just hatched weigh 
about 

Grs. 
I 

After their first moulting, . . . 15 

" " second " . . . 94 

" third " ... 400 

" " fourth . . . 1628 

On attaining their greatest size and weight, 95 00. 

XIII. Of the cocoonery 2J\<\ feeding. 

A room with windows on all sides except the 
east is preferable. Perfect ventilation is of the 
utmost importance: for this purpose numerous ven- 
tilators must be made. 

The worms not being of a wandering disposition, 
are placed on frames or "trays," the most convenient 
size being two by two and a quarter feet. A tray of 
this size will hold from four to five hundred worms. 

On the bottom of the trays, twine or cane may 
be stretched across, forming a network on which 
the worms are placed. 

In feeding young worms (i. e. worms not yet too 
large to crawl through the meshes of mosquito net- 
ting), place a piece of mosquito netting of a conven- 
ient size to cover all the worms, over them ; on top 
of this put a number of pieces of mulberry leaves : 
the healthy worms will soon crawl up on to the fresh 



leaves, and the stale leaves underneath may be 
removed. 

In feeding older worms, place the leaves on top 
of the worms, and remove the litter as often as pos- 
sible. (It may be appropriate to remark here, that 
the warmer the atmosphere in which the worms are 
reared during the first age, the sooner will they spin 
cocoons ; the only economy in having worms to spin 
soon is in the time saved, as they consume the same 
quantity, of leaves during the caterpillar period, 
no matter what the temperature was in which they 
were reared.) 

Silkworms naturally are quite hardy. If they 
are attended to as described above, they will not be 
subject to any disease; but they are frequently 
reared in damp places or in impure air, which will 
produce the diseases which are described in the 
next section. 



SECTION II. 

THE DISEASES OF SILKWORMS. 

As already remarked, the diseases of silkworms 
are generally the result of bad treatment. Their 
causes and remedies are as follows : 

I. Diseases in consequence of defective eggs, 
or in preserving them. The worms will become 
diseased — 



First — When the room where the moths are 
laying eggs is damp, the evaporation will be very 
slow and the eggs will not become dry enough. 

Second — When the place where the eggs are 
kept during the winter is damp. 

No diseases will occur if the eggs are kept dry. 

II. Diseases in consequence of the tempera- 
ture not being regulated properly will occur — 

First — When the eggs that are about to hatch 
are suddenly exposed to any great change of tem- 
perature, either warmer or colder. 

Second — When the worms that are just hatched 
are brought suddenly into a much higher tempera- 
ture ; for the greater the degree of heat the greater 
will be the evaporation, and this will affect the 
delicate organs of the newly hatched worm very 
severely. 

The first organs affected by the diseases pro- 
ceeding from the causes above enumerated are the 
reservoirs containing the silk ; and should they 
become very greatly affected, the worm will usually 
die before reaching the time for spinning its cocoon. 

These diseases can never happen — 

First — If the worms are kept in an even tem- 
perature; and 

Second — If, in removing the worms, they have 
not been exposed to draughts of damp air. 



III. Diseases, not generated in the eggs, arising 
from defective management, are caused — 

First — By placing the worms too thick on the 
trays, thereby hindering them from feeding comfort- 
ably. 

Second — By not keeping the air dry and in 
constant circulation. (This impedes the breathing, 
and causes the leaves on the trays to ferment. If 
this is continued, it will make the worms unhealthy, 
and probably cause their death.) 

Third — By giving the mulberry leaves to the 
worms when not sufficiently dried ; for water is fatal 
to silkworms. 

TJiese can be prevented — 

First — If the worms are evenly distributed on 
the trays, and are not too much crowded. 

Second — By renewing the air, and keeping the 
cocoonery dry. 

Third — By drying the leaves thoroughly before 
giving them to the worms. 

It may also be appropriate in this connection 
to state — 

First — That keeping the cocoonery light is of 
great benefit to the worms. 

Second — That keeping some purifier, such as 
charcoal or chloride of lime, in the room, will pre- 
vent a great many of the diseases of silkworms. 



We have given some of the causes producing 
sickness in silkworms, and the means by which they 
may be prevented ; we will next give a description 
of the most common diseases arising from the 
aforenamed causes. 

I. THE YELLOWS. 

The yellows is probably the most common 
disease to which silkworms are liable. It is accom- 
panied by the following symptoms : 

First — The head of the worm swells ; 

Second — The skin is drawn tight over the rings 
of the body, making it look as if varnished ; 

Third — A yellow liquid is discharged, which 
may be observed on the leaves. 

When any worm becomes affected with this 
disease, it will avoid other worms, seeming to know 
that if a healthy worm should touch this yellow 
liquid it would become infected with the disease. 

As soon as any evidences of the yellows appear 
in any of the worms, the unhealthy should immedi- 
ately be removed, as the disease is very contagious. 

Remedy. — Sometimes, if the worm is not too 
far gone, removing it into purer air may restore it to 
health ; hence, the obvious cause of this disease is 
the impurity of the air. 

Persons living in the country, and raising silk- 
worms, must be careful not to throw any diseased 

*3 



worms where the poultry could find them to eat them, 
as they would be likely to be poisoned by them. 

II. THE TRIPE SICKNESS. 
In this disease, the worm, although dead, still 
appears to be alive. In order to ascertain whether it 
is dead or not, it must be touched, when it feels 
somewhat like tripe: hence the name. 

III. THE SCARLET. 

This disorder dries the rings of the body up, 
and stupefies and cramps the worms. 

As its name indicates, it turns the worm red 
at first, which, however, in later stages of the disease 
changes to white. 

These are the principal diseases of silkworms 
occurring during the caterpillar period. They all 
result from bad treatment, and will never occur in 
a well-regulated cocoonery. The care of rearing 
during this period should be particularly attended 
to, for worms that are ill-managed will neither spin 
perfect cocoons nor will they .emerge as healthy 
moths, and consequently will not lay healthy eggs. 
Imperfect cocoons can not be sold at market rates 
of good cocoons, but go with that class known to 
the manufacturers as waste silk, the price paid for 
which is very low. 



H 



SECTION III. 

PERIOD WHEN THE WORMS ARE 

PREPARING TO SPIN THEIR 

SILKEN COCOONS. 

Silkworms prepare to spin their cocoons in 
about thirty days after hatching. It is very im- 
portant to know when the worms are about to spin, 
in order that preparations may be made accordingly. 

When any worms appear as follows, they are 
likely to spin in less than twenty-four hours after 
being examined: 

First — -When fresh mulberry leaves are placed 
on the trays and the worms do not eat them, but 
merely crawl upon them, and when they erect their 
heads. 

Second — When, on holding the worm up 
toward the sun, it appears to be somewhat trans- 
parent and of a straw color. 

Third — When large numbers of the worms 
leave the centre of the trays and crawl up along 
the framework which supports them. 

Fourth — When their bodies become much 
thinner up near the head and about the neck, caus- 
ing the skin to become wrinkled ; and feel softer 
than they do ordinarily. 

15 



Fifth — When the rings of their bodies are 
drawn tight around them, and the whole body 
changes to a light yellow color. 

When these signs appear in any of the worms, 
preparations for spinning must be made immediately, 
in order that those worms that are ready to spin 
shall not lose their strength and silk in hunting for 
the support requisite for the perfect formation of 
their cocoons. 

All the worms hatched on the same day will 
not spin on the first or second day after the first 
have spun, but the majority will. Those that will 
not should be removed and placed in a warmer 
atmosphere, in order to accelerate their movements. 

In order that the silk may be gathered with 
ease, various receptacles for the cocoon are used by 
different silkworm rearers ; however, for those rais- 
ing but a small number of cocoons, paper cones or 
funnels are about the cheapest and best; for the 
cones are more like the leaf of the mulberry tree, in 
which the silkworms naturally like to spin. The 
cone also economizes the silk used in the formation 
of the " floss silk," or that used to support the 
cocoon, hence leaving more silk with which to 
form the cocoon itself. 

Bunches of twigs, arbors, etc., are also used 
extensively ; but the advantages of cones over these 
are obvious. 

16 



J 



SECTION IV. 

CHRYSALIS PERIOD. 

The silkworm requires four or five days to 
complete the formation of its cocoon ; most cultiva- 
tors, however, allow seven or eight days to elapse 
before gathering them. 

When the cocoons are gathered, and the floss 
silk removed, they are divided into nine qualities : 

First — Good cocoons. They seldom attain to 
any great size, but they are compact and spotless. 

Second — Cocalons. These are larger than good 
cocoons, but contain about the same amount of 
silk, being less compact. 

Third — Pointed cocoons. Cocoons of this 
kind are very difficult to reel, and often can not be 
reeled at all. They have one end rising in a point, 
and the silk, when it reaches the pointed end, will 
very likely break. 

Fourth. — Double cocoons or Dupions. The 
fibres are interlaced. They are formed by two or 
more worms spinning in the same cone at the 
same time. They can very seldom be reeled. 

Fifth — Sufflons. These are very imperfect, so 
much so as to be transparent. They are usually 
not reeled, as they contain very little silk. 

i 7 



Sixth — Perforated or pierced cocoons can 
not be reeled in water, but sometimes they can be 
reeled around the finger without the use of water. 
They have an opening in one end, through which 
the moth has emerged. 

Seventh — Good choquettes. The worms in 
these have died ; if shaken, they do not rattle. The 
silk which they contain is as fine as that of good 
cocoons, but it is not so good for manufacturing 
purposes. 

Eighth — Bad choquettes. These are spotted 
and rotten cocoons, produced by unhealthy worms. 
They are of a dark color and are not worth reeling. 

Ninth — Calcined cocoons. They are of more 
value than any other quality of cocoon, but are 
very scarce. The worm inside, after having com- 
pleted its cocoon, becomes petrified, or converted 
into a white powder. 

Pointed and pierced cocoons, dupions, sufflons, 
bad choquettes, the waste in reeling, and the floss 
silk, are taken together, and form an article known 
as waste silk, which is spun into yarn. 

The chrysalis remains in the cocoon from 
fifteen to twenty days. 

For the purpose of breeding, an even number 
of male and female cocoons must be selected. The 
male cocoons may generally be distinguished by 



being considerably compressed in the middle, 
smaller than the female, or by having one extrem- 
ity much more pointed than the other. 

It is a great advantage to those who do not 
reel the cocoons to sell them as soon as gathered, 
as they weigh more then than at any other time. 

The first object of attention, after the cocoons 
have been gathered, is to choke or " stifle " the 
chrysalides, which is generally done in one of the 
following manners : 

I. By the solar rays. 

Select a clear warm day; spread the cocoons out 
on a cloth, and place them in the sun, being careful 
to keep the ants away. 

Keep them exposed in this 'manner for four or 
five hours during the middle of the day, for five or 
six days, and the chrysalis will usually be stifled. 

In order to ascertain whether life is extinct or 
not, strip the silk from a cocoon and stick the 
chrysalis with a needle ; if no signs of animation 
are evident, the stifling has been completed. 

II. By the heat of an oven. 

Place the cocoons to be stifled in long shallow 
baskets, and put them in an oven whose tempera- 
ture is about 200° Fahr. Let them bake for about 
two hours. When taken out of the baskets they 



must be spread out until perfectly dry, when they 
are ready for the market. 

III. By the use of alcohol. 

Put the cocoons in a box, as nearly air- 
tight as possible. First put in enough cocoons to 
make a layer six inches deep. Upon every super- 
ficial square foot of these, sprinkle half a pint of 
alcohol. Place layers of six inches each, one upon 
the other (sprinkling each layer), until the box is 
filled. Let them stand for twenty-four hours, and 
during that time sufficient heat will be created to 
stifle the chrysalides. 

IV. By camphor. 

Line the inside surface of an ordinary barrel with 
paper, so as to make it nearly air-tight. Use about 
a pound of camphdr to the barrel. Sprinkle a little 
in the bottom of the barrel, put in six or seven inches 
of cocoons, then sprinkle a little more camphor, 
and so continue until the barrel is filled. Close the 
barrel, and let it stand for two or three days. 

After the stifling has been completed by any 
of the means described, the cocoons should be 
placed on cloths and dried, in order to preserve 
them from moulding, w T hich is very likely to occur. 
When thoroughly dried, they can be packed in 
boxes and sent to the market. 



SECTION V. 

PERFECT PERIOD. 

The moths, or perfect insects, issue from the 
cocoons in the morning from four to nine o'clock. 

As soon as they pierce their cocoons, they are 
placed in a dark room on pieces of blotting paper, 
until they discharge a liquid of a light brown color. 
As soon as this is discharged, which is usually in 
five or ten minutes after they emerge from the 
cocoon, they should be placed on sheets of card- 
board and mated. After ten or twelve hours have 
elapsed, they maybe separated, and the males thrown 
away. Now place the female moths on large pieces 
of paper, card-board, or linen, for the purpose of 
laying their eggs. The cards on which the moths 
are to lay their eggs are tilted at an angle of 45 °: 
this will cause the moths to lay their eggs closer 
than if the surface is horizontal. 

The number of eggs .laid by each female moth 
varies from 300 to 450. 

The eggs, when laid, are of a yellow color, 
which, if the eggs are not defective, changes in a 
few days to a bluish gray. 

In this climate, there is no danger of eggs laid 
late in the summer hatching before December ; but 
after that time they must be kept in a temperature 
below 40 Fahr. 



An ounce of eggs (576 grains), is found to con- 
tain 40,000 (39,168), and can be produced from 120 
female moths. 

The greatest precautions must be taken to 
preserve the eggs during the winter in a perfectly 
dry place ; and they should be looked at occasion- 
ally, to see that no mould gets on them. 

These are the principal points that must be 
attended to previous to the process of reeling. 
Reeling is usually carried on as a business distinct 
from that of rearing the worms, or else it would have 
been described here. 

Every fact recorded in this book must be at- 
tended to strictly, or else success will be very un- 
certain. Only the most important facts are men- 
tioned ; but anything further respecting the rearing 
of silkworms or the sale of cocoons, will be given 
gratuitously by addressing 

THE BOYS' SILK CULTURE ASSOCIATION 
of the United States, 
Main Cocoonery, 700 N. Eighth Street, 

Philadelphia, Pa. 

the end. 



ROTHERMEL & ReGER, 



COAL 



1063 an( i I0 ^5 Germantown Ave. 



PHILADELPHIA. 



LIBRARY OF CONGRESS 



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